Vanuatu's long stretch of islands means the climate varies considerably between the tropical north and the subtropical south. But whenever you come you're pretty much guaranteed pleasant weather. From January to July the average high drops from 28°C (83°F) to 24°C (76°F), likewise lows move from 23°C (73°F) to 19°C (67°F). The prevailing winds throughout the year are from the southeast (the famous Southeast Trade Winds of sailing ship days), bringing sunny days and cool nights. However, in the wet season the winds are more variable. Squalls can blow up in a few minutes, reaching 90km/h (56mi/h)and presenting a real danger to any small sailing vessels. The 'Summer' rainy season is November to April,and sudden tropical showers can occur anytime. May to July are the optimum months for hiking - cooler and drier, and June to September - evenings on the southern islands can even be brisk. Vanuatu is the most cyclone-prone country in the South Pacific. Any given locality can expect to be hit by a cyclone every other year (usually between January and April). The southernmost islands however are less vulnerable to cyclones, and get less rain than the hotter islands north of Efate.